Fan and propeller.



W. l. A. ILONDON fin H. R. TROTTEK.

FAN AND PROPELLER. APPLICATION men on. 3. 1916.

11x31 Pmm. A r". 23,1918.

' INVENTOR-S fl V? KWQM/ A TTORNE Y.

JEAN it I mean.

l J. A. LQJN'JDON, 0F In, MASSACHUSETTS, AND HENRY R. TEOTTER, 0F

' w. SOB, CONNECTICUT;

.JPROPELLER.

' Patented Apr, 23, Thu

Application filed 0etober 8, 1916. Serial No. 1,23,4l67.

TER, a citizen of Great Britain, residing at Windsor, Connecticut, have invented a new and useful Improvementin Fans and Propellers, of which the following is a specification.

This invention relates to the manufacture of the blades of high-speed ventilating and draft fans and air propellers.

The object of the invention is to by simple means reduce the sound caused by the revolution of the blades of high-speed fans and propellers, and at the same time so stifi'en the blades that they may be made of light material and yet withstand the heavy strains to which they are subjected when driven at high speed. i

This object is simply attained by setting the leading edges, 01' edges on the intake or front side of the blades of fans and air propellers, into rounded tubes or rods which engage the inrushing air without the disturbance or shock incident to thin sharp edges and which stiffen the blades so that when made'thin they will not break or collapse. These features are of particular advantage in fans designed to rotate at, say, 2,000 revolutions per minute, when used on destroyers and the like vessels in ventilating and furnace draft systems where the elimination of noise and reduction in weight is exceedingly desirable.

The invention is illustrated and described herein as embodied in a high-speed multi le-bladevertical-shaft turbine-driven venti ating fan. Figure 1 shows a plan of a form of such a fan. I Fig. 2 shows. a diametric section. Fig. 3 shows a bottom view of the same. Fig. 4: shows on lar er scale a peispective view of one of the bla es of such a an.

Projecting from the hub 1 of the fan illustrated is a base cone or shell 2. The outer conical shell 3 and the intermediate conical shell 4: (and there may be any desired number of intermediate shells) are fastened'to the base shell by tubes or rods 5tubes being shown in the drawings. These tubes, of which there will be the same number as it is designed to have blades, may be headed over at the en so as to fasten them to the base shell and outer shell, and between the shells the tubes are provided with longitudinal slots. The inner edges of the blades 6 are inserted'into the tubes through the slots and are fastened thereto. The side edges of the blades are turned out to form flanges 7 breaking. Furthermore, and what is of particular advantage in this construction, is that while forming light rigid supports for by means of which they may be riveted to the shells and simple reinforcements for the edges of the blades, the rounded tubes so engage'and influence the course of the inrushing air that the noise usually incident to the operation of these fans is very materially reduced, which is of great advan*' tage in high-speed fans and propellers which are used in places where it is essential to have the fan run as quietly as possible.

The invention claimed is:

1. A fan or propeller having a hub, slotted supports mounted on the hub, and blades with their leading edges secured in the slots of said supports.

2. A. fan or propellerhaving a hub, slotted tubes mounted on the hub, and blades having their leading edges inserted through said slots and secured in said tubes.

3. A fan or propeller havin a hub,

conical shells carried by the hu slotted tubes connecting the shells, and blades with their leading edges inserted through the slots into the tubes and their side edges secured to the shells. 4. A fan or propeller blade comprising a thin wing, and a circular slotted reinforcement fitted onto theleading edge of saidwmg.

WILLIAM J. A. LONDON. HENRY R. TRUTTER. 

